The no spark with the Chinese atv seems to be a epidemic around here.
Well I going to add to it also as I need little help. I think I am needing new cdi box but thought would ask first. I am working on a Sunl 150cc atv with an ac cdi box and I went down through this list that I found for the six pin ac cdi box and below are my values I received during my testing.


To troubleshoot no spark problems on a 6 pin AC powered CDI it makes sense to start in the middle (the CDI), measure as much as we can and branch out from there. For the CDI to do its thing it needs power, a trigger pulse, and it must must be inhibited via the kill switch input pin.



1) Unplug the CDI. Turn the ignition switch on. Set all kill switches the the "run" position. In the wiring harness, measure the resistance of the kill switch pin to the ground pin on the 20K ohm scale. It should read infinite ohms (same as when the meter leads are hanging free and not touching anything). It should not read zero ohms (shorted).


2) Leave the CDI unplugged. Use a meter to measure the resistance of the AC ignition power pin in the wiring harness to the ground wire on the 2K ohm scale. You should read approximately 400 ohms. What do you measure?


3) In a similar fashion measure the resistance of the Ignition Trigger Pulse pin to the ground pin. You should see 150 ohms or so. What do you measure?


4) Switch your meter over to measure AC volts on the 200 volt scale. Leave the CDI unplugged. While cranking the engine, measure the voltage on the AC Ignition Power pin in the wiring harness to the ground pin. You should measure 40 to 80 volts AC. What do you measure?


5) Set your meter down to the lowest scale you have for measuring AC volts. 2 volts would be ideal, but some meters don't go that low. In that case use the lowest scale you have. While cranking the engine, measure the voltage on the Ignition Trigger Pulse pin in the wiring harness to the ground pin. You should measure 0.2 to 0.5 volts AC. What do you measure?


6) Now plug the CDI back in. Measure the AC voltage on the Ignition Coil pin to the ground pin using the 200 volt scale. If you have to, use a sewing pin to poke through the wire insulation and then put the meter probe on the sewing pin. But don't hold your fingers on the connection during the next test - there may be high voltage here when the engine is turning. With the ignition on and all kill switches set to the "run" position, crank the starter motor. You should see voltages bouncing around at random values and the meter captures all or part of a spark event. What do you see?


1) shows 1. or open
2) 508 ohms
3) 141 ohms
4) 74 volts
5) .26 volts
6) 00.4 - 00.5 volts

 

Sounds like a bad CDI to me too based on your measurements.

 

Thanks for the reply. I was leaning toward that but just wanted to check first, and this site seems to help people out with good information.

 

Please let us know how it turns out .

 

will do. I ordered the cdi from Sunl parts as soon as you confirmed my suspicions. I just received an email update to my order today saying that it has been printed. LOL At this rate we may be waiting awhile to find out.

 

Well I received a cdi box from sunlpartsonline.com. I ordered an ac cdi box per their webpage picture and the description says ac also. Well way my luck is of course I got a dc cdi box with the same part number on the sticker on the bag. I told them about the web page error. Hopefully they will get it changed because I am sure a lot of people take it for granted that if the box plugs in it correct and of course it won't be. Anyway I sent it back and am waiting again.

 

Bummer about the wrong CDI. But I'm curious about how you know that it is a DC CDI? You can't tell by looking, so unless there is a label saying "DC powered" on the CDI, or something like that, then how would you know?

You're right about sales people not knowing about what they sell. Even seasoned, very good mechanics often have trouble when it comes to electrical stuff....

 

the package I received had the same part number as the webpage with the exception it had DC on the end of it. And there is a slight difference in the dimensions of the boxes. The DC box is little bigger than the AC model. They have same plugs but different sizes. Below is a picture I took before sending box back. Its not best picture but you can see the new DC box in the bag is larger than the AC model on the right.

 

Well so much for getting my shipping costs back as they promised. But I did finally receive the cdi box that I ordered this morning and installed it and low and behold we have spark. Thanks for the help.

 

I'm glad it is working for you .